Video systems in vehicles are used in particular to realize various primary driver assistance systems, e.g., night vision systems, video warning systems, lane recognition, lighting assistance, etc. Here, the camera acquires the environment surrounding the vehicle through a vehicle window, in particular the front windshield. In general, here the object distance is set to infinite. Other regions having finite object distance are then however not imaged sharply.
Furthermore, cameras are also conventionally used for secondary functions, e.g., the detection of raindrops on the external surface of the window; here, in general light, in particular infrared radiation, is radiated into the window and is detected using the imager of the camera. In such systems, a separate imager region can be provided for this radiation. However, such systems require an additional outlay that is specific to the vehicle or to the window.
U.S. Patent Application Publication No. 2007/0096010 A1 describes a multifunctional optical sensor as a CCD or CMOS element whose sensitive surface is divided into subregions provided for different functions. Here, microlenses or microprisms are placed before the individual pixels in order to achieve desired imaging characteristics, in particular focusing characteristics. In this way, the overall optical system is formed by these microlenses or microprisms. However, this requires very expensive and vehicle-specific designs of, for example, the microprisms.
The acquisition of different acquisition regions by a camera using a single imager is also described in, for example, German Patent No. DE 103 23 560 A1. Here, on the one hand a region outside the vehicle is acquired for driver assistance functions, via a first imager region. In addition, a mirror, in particular a convex mirror, is used to acquire a region above the vehicle, in particular vertically above it. In this way, a brightness signal can be produced as a function of the image signals. Such systems already enable versatile use of a single imager or image sensor for a plurality of functions. However, a significant apparatus outlay is required, due to additional convex mirrors or other optical devices provided externally or before the objective of the camera.